I have a 2003 and it has a high speed vibration problem that starts at about 100 mph and is the most promenant at about 110 mph. It is like a thumping that is not in the steering wheel and you can feel it through the chassis. It was there with my stock wheels and with my new Nismo wheels so I do not think it is a wheel balance problem ???

 

Driveshaft balance, maybe. Just guessing, though. I had a similar vibration in my 300ZX, it was the drivshaft. Is it still present when you are coasting?

 

Dude, 110mph. It isn't going to drive like glass at that speed.

My 03 is pretty smooth >= 100mph but there is some vibration in the steering wheel. Not sure what it is.

 

What's the weather when you have vibration? The road is wet or dry? If ur car have vibration only durring rain/wet road. It will be your rims. But I'm not mean that ur rims is demage. It's because of rims's inner design.